HAV is vibration transmitted from work processes into workers’ hands and arms. It can be caused by operating hand-held power tools such as roadbreakers, hand-guided equipment such as lawn mowers, or by holding materials being processed by machines such as pedestal grinders.
Regular and frequent exposure to high levels of vibration can lead to permanent injury.This is most likely to occur when contact with a vibrating tool or process is a regular part of a person’s job. Occasional exposure is unlikely to cause injury, although it should be avoided by people with medical conditions such as Raynaud’s Disease
Regular exposure to HAV can cause a range of permanent injuries to hands and arms, collectively known as Hand-Arm Vibration Syndrome (HAVS). The injuries can include damage to the:
- blood circulatory system (eg vibration white finger)
- sensory nerves
- muscles
- bones
- and joints
The injuries can be painful and disabling, for example:
- painful finger blanching attacks (triggered by cold or wet conditions)
- loss of sense of touch and temperature
- numbness and tingling
- loss of grip strength
- loss of manual dexterity
In addition, they may affect work and leisure activities. People may:
- need to avoid further exposure to vibration, or cold and wet conditions
- have difficulty handling tools, materials and completing tasks that require fine finger manipulation
HSE estimates that there are around 36 000 people with an advanced stage of Vibration White Finger (VWF). This is the most well-known form of Hand-Arm Vibration Syndrome.Hundreds of new cases of VWF are assessed each year by the Department of Social Security under the Industrial Injuries Disablement Benefit scheme. VWF is also one of the most common reasons for occupational ill health claims made against employers.
Jobs requiring regular and frequent use of vibrating tools and equipment are found in a wide range of industries, for example:
- building and maintenance of roads and railways
- construction
- forestry
- foundries
- heavy engineering
- mines and quarries
- plate and sheet metal fabrication
- public services (eg maintenance of watercourses, roadside verges and parks)
- public utilities (eg water, gas, electric, telephone).
There are hundreds of different types of tools and equipment which can expose operators to high levels of hand-arm vibration. Some of the more common ones are:
- chainsaws
- concrete breakers/road drills
- hammer drills
- hand-held grinders
- hand-held sanders
- nut runners
- pedestal grinders
- power hammers and chisels
- powered lawnmowers
- riveting hammers and bolsters
- strimmers/brush cutters
- swaging machines
Equipment manufacturers are generally trying to improve the vibration performance of their products, so new tools and machines are likely to emit lower vibration than older equipment. You will gain the maximum benefit from these improvements if you introduce a policy of buying the most suitable equipment when you replace tools or machines.DEWALT prides itself on innovation and therefore its range of hammers and many other products are some of the most up to date products on the market. Focusing on controlling vibration at source (Active Vibration Control), DEWALT’s range of products demonstrate some of the lowest vibration products available. For most types of equipment, manufacturers are required by law to:
- design and construct equipment which will cause minimum risk of vibration injury
- provide you with warning of any residual risks from vibration
- provide you with information on vibration levels and provide you with instructions on how to use the equipment to avoid risks from vibration
Health and Safety law requires you to do a number of things to protect your employees. You should:
- assess the risk to the health of your employees and plan for its control
- manage the risk
- provide suitable equipment for your employees’ to use
- maintain equipment correctly
- give your employees information and training on health risks and safe use of the equipment
- provide health surveillance of your employees where risks cannot be completely eliminated
- provide reports to the relevant enforcing authority on cases of HAVS in your workforce
- consult your safety or employee representative on your proposals to deal with vibration hazards
The documentation supplied by the equipment manufacturer should warn you of risks from vibration.You can also check yourself to see if hand-held power tools, hand-guided and hand-fed machines are regularly used, and if so, whether anyone is, in particular:
- using hammer action equipment for more than half an hour each day
- using rotary or other action equipment for more than 2 hours each day.
If so, your employees are probably at risk. Even where employees are using vibrating tools or machines for less than these times, there may still be a risk and you should regularly (at least every six months) ask them if they are getting any symptoms of HAVS. Some simple questions you could ask are:
- Have your fingers gone white on exposure to cold?
- Have you had any tingling or numbness in your fingers after using vibrating equipment?
- Are you experiencing any problems with muscles or joints in your hands or arms?
- Do you have any difficulty picking up small objects such as screws or nails?
If the answer to any of these questions is ‘yes’, assume that there is a risk from HAV to your employees. You should refer the employee to a doctor and take action to reduce exposure. There is more detailed guidance on what you can do to assess the risk in HSE’s publication 'Hand-Arm Vibration'.
- There are many things you can do, several of which may cost very little and could also improve productivity and product quality, for example:
- Look for alternative ways of working which can reduce the amount of work with vibrating tools.
- Make sure your employees use the most appropriate equipment for each job (inappropriate equipment may take longer to do the job or vibrate more).
- Minimise the time individuals use the equipment, eg job rotation.
- Break up periods of continuous equipment use by individuals (introduce other tasks).
- Design the job so that poor posture (which may cause strain on hands and arms) is avoided.
- Construct jigs to hold materials or tools.
- Reduce the gripping and pushing force on the tool. The tighter the grip and more force used increases the exposure without necessarily reducing the time to do the job. Let the tool do the work.
- Maintain tools to the manufacturer’s specifications to avoid worsening vibration. For example:
- replace vibration mounts before they are worn out;
- ensure rotating parts are checked for balance and replace them if necessary
- keep tools sharp.
- Get advice from your trade association on best practice.
- Get advice from the equipment manufacturer on safe use of the equipment.
- Where there is excessive use of high vibration equipment, find alternative ways to achieve the task which reduces the use of such machines.
- Ask the manufacturer to suggest the most productive tool for the job. A more powerful machine can do a job faster and may reduce the overall vibration exposure.
Employees need to know about the hazard and what they should do to reduce the risk,
- potential sources of hand-arm vibration;
- the health effects of hand-arm vibration;
- risk factors (eg high levels of vibration, daily length/regularity of exposure);
- how to recognise and report signs of injury;
- ways to minimise risk, including:
- changes to working practices to reduce vibration exposure;
- correct selection, use and maintenance of equipment;
- how to use tools to reduce grip force, strain etc;
- maintenance of good blood circulation at work, eg by keeping warm, exercising fingers and not smoking.
You should consult with your safety or employee representative on your proposals for training and information.
Even where you have taken precautionary measures, some employees may still be at risk. In cases where regular exposure to hazardous vibration continues or employees are reporting symptoms, you need to arrange for regular health checks (known as health surveillance) of those employees.This should mean that harm from vibration is detected early and will allow you to:
- arrange for a medical assessment and for medical advice to be given to the employee about the risks of continuing exposure;
- take steps to avoid serious injury of the employee.
The health surveillance programme should be under the supervision of a suitably qualified medical practitioner who may train people, for example a nurse or first aider, to help with the administration of the programme. Non-clinical information can be fed back to you so that you can check whether your control measures continue to be effective.
- questioning about symptoms;
- completing questionnaires (there is a sample in HSE’s publication HSG88 Hand-Arm Vibration)
- physical examination
- advice to the employee.
Regularly questioning your employees about symptoms will let you know if there are still problems. If you arrange health surveillance the occupational physician will also advise whether your controls are working effectively.
Introduce a vibration purchasing policy in consultation with your managers and safety or employee representatives. Through this policy you should ensure that any decisions are made on the correct tri-axial data as opposed to single-axis data. If it is not specified then you should assume the data is single-axis and treat it accordingly (see 'Measurement Section'). In addition, ensure that you are not purchasing poor performing tools which take longer to complete the task and could ultimately lead to higher exposure to vibration. A high performance to vibration ratio is key.
This depends on a number of factors including the level of vibration which reaches the hands and how long they are exposed to it. The people most likely to be harmed by vibration are those who regularly use high-vibration tools and machines. For some people, symptoms may appear after only a few months of exposure, but for others it may take several years.